Monroe Electronics Resistivity Meter - Portable - Surface - model 272A User Manual
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Figure 1
Setup for Surface Resistivity Measurement
CONFIDENCE CHECK:
As shipped from the factory, the default settings for the Model 272A are to measure surface
resistivity using the probe provided at an applied voltage of ten volts and to display the result in
scientific notation similar to that shown below:
To demonstrate this, connect the probe to the Model
272A by attaching the coaxial plug to the mating
connector on the front panel and inserting the
miniature banana plug into the jack directly above.
Included with the Model 272A is a Specimen Support
Surface-a metal plate with an insulative surface-and a
cable with banana plugs on each end. Connect this
cable between the hole on the side of the plate and
the metallic jack on the side of the Model 272A. Place
an ordinary sheet of common notepad paper on the
insulative surface of the plate and set the probe on
top of the paper. Press the ON-OFF switch. A brief
announcement will appear on the screen and, if the
factory settings have not been disturbed, the
message shown above will be displayed within a few seconds. The value will probably be
different. Common paper generally will have a resistivity within the range of the instrument
under normal ambient conditions allowing some value to be displayed.
The above illustrates how the display reacts to a resistivity measurement wherein the applied
voltage is impressed across the material (or lack of material) between the circular electrodes of
the probe and the Model 272A interprets a factor specific to the probe to produce a correct
value readout in ohms per square. Now, lift the probe by its handle. Within a few seconds, an
error message should be displayed (see ERROR MESSAGES):
OPERATING CONTROLS:
In addition to the ON-OFF push-button switch, there are two other operator controls-push-button
switches labeled OHMS-OHMS/SQ and 10V-100V. These may be used to temporarily toggle
the function or the applied voltage. Once the instrument is shut off or powered down
automatically, the power-up default settings are restored.
SURFACE RESISTIVITY MEASUREMENTS:
The method for measurement of surface resistivity of sheet materials using the probe provided
is given in “CONFIDENCE CHECK” (above).
Custom miniature probes in point-to-point and guard ring configurations are available for
measuring irregularly shaped objects such as DIP tubes and thermo-formed plastic carriers.
1.2E10 / @10 V
VALUE TOO HIGH
2
7
2
A
9
6
1
0
1
A
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E
N
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N
S
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A
T
E
D
S
I
D
E
U
P
/
/
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E
T
T
O
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